The very first step you must go for is open Sony Mobile.com and after that Xperia P tab.

Depending on the browser you use you must check out what updates are available.

Now if you have a PC or Mac, connect your phone to that device. With this there would be phone identification and the search for new software would begin.

Once the software is traced and located you will get more information on that particular new update or new software.

Now, click on Update and with this the process will get started. But just see to it that the connection between the phone and PC or Mac still remains.

When the update process gets finished you must disconnect Xperia P from Mac or PC.

You may experience localized updating and this may take a few minutes.

Now the device will get rebooted.

That’s it. You can now use Xperia P with the update. But kindly follow the procedure at your risk.

There are many people who might have installed ICS on Xperia P, but they might not have rooted their Android phones. In that case, we would like to provide you instructions to root Sony Xperia P on ICS. We give credit for this method to XDA senior member royalbloodvi who have opened the way to install Google Now on Xperia P with ICS. This is because for installing Google Now on ICS you need the rooted phone. You will be able to enjoy Google Now on rooted Xperia P with ICS.

Here are the step by step instructions to root Sony Xperia P on ICS. But kindly read the disclaimer first.

Disclaimer: Rooting an Android phone can be a bit risky. This is because you will lose the warranty. Also, there are rare chances of data loss and/or phone bricking. Thus we suggest that if at all you wish to do it, you must have enough technical exposure. Do it at your risk.